VALIDAÇÃO DO MARCADOR SNP 7 PARA USO NA SELEÇÃO ASSISTIDA DE GENÓTIPO DE ARROZ TOLERANTES À SECA

Abstract

Rice production is critical to food security in the world. Drought occurrences are unpredictable, and when they occur in the reproductive stage, they can result in the total loss of production. There is genetic variability for drought tolerance in rice, but conducting experiments is difficult and costly. This work aimed to validate the SNP7 (A/G) marker, developed at Embrapa Rice and Beans, for use in assisted selection for drought tolerance in a germplasm collection different from that used in the identification of this marker. Seventy-two accessions from the Drought Tolerance Thematic Collection were studied in an experiment in a randomized block design, with 3 replications and two irrigation systems - water deficit and irrigated. The plots consisted of four rows of 3.0 m, spaced 0.35 m apart, and the sowing density used was 80 seeds per meter. The drought treatment started 35 days after planting, maintaining the water tension in the soil of up to 25 kPa until physiological maturation. Accessions were evaluated for yield, 100-grain weight (PCG) and sterility. SNP7 genotyping was performed using the TaqMan assay via quantitative PCR. Considering the water deficit treatment, the 25 accessions with the G/G genotype for SNP 7 were significantly more productive (p<0.001), with higher PCG (p<0.05) and lower sterility (p<0.05) in relation to the 47 accesses A/A. SNP7 represents a major breakthrough for the development of drought-tolerant rice cultivars, through the selection of parents and progenies that have the G/G genotype.